Oh, I got in trouble for being clever once.
I had a PanelView Plus with a big multi-state text indicator that essentially functioned as a Help window: depending on the fault or condition, a large block of text would show up.
These also have an error condition: if the display value doesn't match one of the State values, or if there's a comms error, it shows the Error state text.
Instead of leaving it blank, I wrote out the text of Lewis Carroll's nonsense poem, JABBERWOCKY. Hey, you memorize something in 6th grade, it's not going away.
Until one day the Ethernet switch in the system failed, and the HMI was filled with asterisks and wireframes. The only thing that showed anything but a blank was the poem.
The customer panicked, concluding that a JABBERWOCKY virus had infected the PanelView. They isolated the whole production line and called their IT incident group.
There is in fact a virus with that name; it's literally a 812-byte Visual Basic script from 1992 with just one line of text and a shout-out to a British virus researcher.
By this time I had long forgotten about what I'd left in the PanelView, and the messages of alarm from the customer were unclear. I went onsite and got thoroughly chewed out by their IT and production managers, and my protestations that they should be more conversant with modern English poetry were unconvincing.